Hypogonadism among patients with transfusion-dependent thalassemia: a cross-sectional study

Introduction: Patients with thalassemia major are liable to have complications from blood transfusion and iron excess despite using iron-chelating agents. It is common to have endocrine complications in these patients. Hypogonadism is one of the most common complications in thalassemic patients. Early detection and treatment are essential to restore puberty and prevent complications from hypogonadism. Patients and methods: The authors conducted this cross-sectional study in the Kurdistan Region of Iraq, from 1 July 2022, to 1 December 2022. Eighty patients with β-thalassemia major who were referred to the endocrinology clinic were enrolled. The patients were evaluated sequentially, starting with a history, followed by a clinical examination and laboratory tests related to endocrine disease. Those who met the inclusion criteria were enrolled in the study, while the others were excluded. Results: Out of 80 patients with major thalassemia who were referred to the endocrinology clinic, 53 (66.3%) were female, and 27 (33.7%) were male, with a mean (SD) age of 24.86±7.66 (14–59) years. Fifty-five (68.75%) of them had hypogonadism, three patients (3.8%) had hypothyroidism, while two (2.5%) had hypoparathyroidism. Five patients (6.3%) had diabetes. None of the patients had adrenal insufficiency. The mean ferritin level in thalassemic patients with hypogonadism and thalassemic patients without hypogonadism was 2326±2625 ng/ml vs. 1220±2625 ng/ml. Conclusion: To minimize the risk of endocrinopathy in patients with thalassemia major, they should receive blood transfusions regularly and initiate chelating agents early, because the leading cause of endocrinopathy in thalassemic patients is related to the severity of anemia and iron overload.

Introduction β-thalassemia is an autosomal recessive disorder that occurs as a result of either a lack of synthesis of the β-globin chains of hemoglobin (β 0) or reduced synthesis of that chain (β 1). It is regarded as one of the most common diseases inherited as a single gene disorder, and about 270 million carriers are present globally [1,2] . Three types of β-thalassemia are described: thalassemia major, which is the most severe form that needs regular blood transfusions, and thalassemia intermedia and minor, which are the mild forms of the disease [3] .
Regular blood transfusion is associated with the accumulation of iron in different tissues in the body [4] . The commonly reported organs that are liable for marked iron deposition are the liver, pancreas, pituitary, thyroid, parathyroid, heart, adrenal, gonads, renal medulla, spleen, and bone marrow [5] . Although the primary cause of death in these patients is heart disease, endocrinopathy, especially hypogonadism, remains the most common manifestation of β-thalassemia major [6] .
Puberty is defined as the development of secondary sexual characteristics, the initiation of fertility, the achievement of adult height, and psychosocial well-being [7] . The hypothalamicpituitary-gonadal axis remains inactive until puberty, after which it will start to maintain growth and initiate secondary sexual characteristics. Delayed puberty is a failure to achieve secondary sexual characteristics by the age of 14 in males and 13 in females, which may be caused by congenital or acquired diseases and has significant effects on both physical and psychosocial wellbeing [8] .
Hypogonadism manifests in males as a testicular volume of less than 4 ml, while in females, it is marked by the absence of breast HIGHLIGHTS • Patients with thalassemia major are liable to have complications from blood transfusion and iron excess despite using iron-chelating agents. • Hypogonadism is one of the most common complications in thalassemic patients. • The leading cause of endocrinopathy in thalassemic patients is related to the severity of anemia and iron overload. • This study aims to evaluate the prevalence of hypogonadism in referred patients with thalassemia major, assess the type of hypogonadism. development by age 16 [9,10] . Hypogonadism in patients with thalassemia major is caused by iron deposition in the pituitary gland, gonads, or both [11] . It has been shown that gonadotrophs need a higher iron level, are more sensitive than other anterior pituitary cells, and are most affected by iron overload [12] . The only effective way to get rid of iron overload is the use of chelating agents [13] . A study conducted in Italy showed a lack of benefit in using iron-chelating agents to prevent the endocrine complications of thalassemia major [14] . In contrast, other studies suggested that using iron-chelating agents reduces the risk of complications, especially endocrinopathy from transfusion-dependent thalassemia, and is associated with a better quality of life [15,16] . The higher the level of ferritin, the more the risk of complications from thalassemia [17] . This study aims to evaluate the prevalence of hypogonadism in referred patients with thalassemia major, assess the type of hypogonadism, and study the relationship with precipitating factors and other endocrinopathies.

Study protocol
This cross-sectional study was conducted in accordance with Strengthening the Reporting of Cohort Studies in Surgery (STROCSS) [18] .
The present study enrolled 80 patients with β-thalassemia major referred to the endocrinology clinic in the Kurdistan Region of Iraq.
The referred patients were evaluated first by taking a detailed clinical history that included the patients' demographics, referral purpose, past medical and surgical history, use of drugs (especially chelating agents and compliance with this kind of therapy), the interval between blood transfusion sessions, and a focused review of symptoms related to the reproductive system. This was followed by a clinical examination, including Tanner staging, height, weight, and blood pressure measurement. Tanner staging, which includes five stages and is different for males and females [19] , was used to decide clinically whether the patient had achieved puberty and whether they were hypogonadal. These findings were then corroborated with relevant laboratory investigations.

Inclusion criteria
All patients with thalassemia major referred to the endocrinology department were included in the study.

Exclusion criteria
Patients were excluded from the study if they were younger than 14 years old or had a history suggesting other causes of hypogonadism rather than thalassemia (for example, a history of trauma to the gonads or the head, radiation, drugs known to cause hypogonadism) and those who had undergone bone marrow transplantation.

Data collection and analysis
Data were taken from the patient's record and from the questionnaire. Data collection, entry, and coding were done using Microsoft Excel Version 2019. The results are presented as the mean SD. Qualitative data were presented as frequencies and percentages. Data analysis was performed using Statistical Package for the Social Sciences (SPSS) Version 26. Continuous variables were compared by the Student's t-test, and discrete variables were analyzed using the χ 2 -test.

Results
In this cross-sectional study, 80 patients with β-thalassemia major referred to the endocrinology clinic were enrolled (Table 1).
Five patients (6.3%) had diabetes mellitus, and none had adrenal insufficiency.
There was no significant difference in the compliance with the iron-chelating agents between TPwH and TPwoH ( Table 2).
The mean ferritin level in hypogonadism was 2326 2625 ng/ml, which was higher than its level in patients without hypogonadism, in whom it was 1220 1785 ng/ml. Hypogonadotropic hypogonadism was more common than hypergonadotropic hypogonadism, with frequencies of 53/55 (96.36%) and 2/55 (3.63%), respectively.
There is a significant difference between TPwH and TPwoH in the level of serum testosterone in males and serum estradiol in females, respectively. Other biochemical tests are illustrated in (Table 3).

Discussion
Thalassemia major is a common hereditary disease in the Kurdistan Region of Iraq, and its prevalence reached 37.3/100 000 individuals in the population in 2020 [21] . This is primarily due to consanguineous marriages and a lack of preventive measures until recently.
Frequent blood transfusions result in excess iron deposition in various organs that may eventually cause dysfunction, especially in the endocrine system.
In this study, the most common manifestation of thalassemic patients referred to the endocrinology department was hypogonadism, with a frequency of 55/80 (68.75%). This is similar to what was observed in a study performed in Saudi Arabia [22] . The prevalence of hypogonadism in transfusion-dependent thalassemia varies, reaching up to 80% in some studies and being as low as 30% in others [23,24,25,26,27] . The high prevalence of hypogonadism in the present study may be related to the fact that we dealt specifically with referred patients suspected to have endocrine complications by their hematologists through history, clinical examination, and investigations.
Compliance with the chelating agents in both groups was poor and nearly the same, which can be explained by polypharmacy, the unavailability of the drugs, and a lack of awareness regarding the significance of this therapy.
There is significant heterogeneity in the epidemiology of hypogonadism in patients with thalassemia, which may be related to the differences in the clinical manifestations and characteristics [11] .
The classification of hypogonadism depends on the level of the hypothalamic-pituitary-gonadal axis affection [29] . An inappropriately normal or low level of LH and FSH in the presence of low estradiol in females and testosterone in males indicates  hypogonadotropic hypogonadism, while in hypergonadotropic hypogonadism, the level of LH and FSH is high. In this study, hypogonadotropic hypogonadism was much more common than hypergonadotropic hypogonadism, with frequencies of 53/55 (96.36%) and 2/55 (3.63%), respectively. This is explained by the higher affinity of gonadotropic cells in the anterior pituitary for iron.
Sometimes there may be changes in both the anterior pituitary gonadotrophs and the gonads resulting from the original pathology, but it is quite difficult to differentiate these two situations, as in hypogonadotropic hypogonadism, there are changes in the gonads as well due to the loss of stimulatory effect on the gonads by LH and FSH.
Although the effect of iron on the testes and ovaries is not well understood, autopsy studies have revealed interstitial fibrosis and pigmented seminiferous tubules with an absence of Leydig cells in the testes [30] .
Many factors affect the development of hypogonadism in patients with β-thalassemia major, including chronic anemia, improper blood transfusions, improper iron chelation (either delayed or poor compliance), and other comorbidities [31,32] .
In the present study, TPwH had more comorbidities, at a frequency of 21.82% (12/55), including liver, heart, and diabetes mellitus, than TPwoH, with a frequency of 16% (4/25). This is mainly related to the same risk factors that affect the endocrine organs.
The ferritin level (mean SD) in TPwH (2326 2625 ng/ml) was higher than TPwoH (1220 1785 ng/ml) and can be regarded as one of the risk factors for developing hypogonadism in transfusion-dependent thalassemia. Abdulzahra et al. and Chowdhuri et al. found a direct relationship between serum ferritin and the development of hypogonadism [33,34] .
There is no significant difference in the splenectomy status in both groups, and this finding is supported by Gamberini et al. and Skordis et al. as they postulated that there is a relationship between a history of splenectomy with hypothyroidism but not hypogonadism [35,36] .
The serum level of vitamin D3 between both groups was comparable. This is compatible with the data reported by Lerchbaum E et al. [37] .
The point of strength of our study is that, it exclusively dealt with the patients with thalassemia major that were suspected of having endocrinopathy, while its limitations included missing data of some patients who were excluded from the study, small size due to the limited time of the study, and measuring serum ferritin level alone as a surrogate for iron deposition.
In conclusion, hypogonadism is the most common endocrinopathy among transfusion-dependent patients with thalassemia major and is related to chronic anemia and excess iron deposition. Regular blood transfusions, proper use of chelating agents, and periodic assessment for the early detection of hypogonadism are key factors in reducing the risk of developing hypogonadism.

Ethics approval and consent to participate
The present study was approved by Kurdistan Board for Medical Specialties Ethics Committee. Written informed consent was obtained from all participants or the parents in the case that the participants were underage.

Patient consent for publication
Not applicable.

Funding
No funding was received.

Author contribution
T.O.M.: supervising the research from the title till the end; Z.G. R.: performed literature review, participated in collecting data, and reviewing grammar of the study; S.F.A.: collected the data, wrote the paper, and submitted it.

Conflicts of interest disclosure
The authors declare that they have no competing interests.